EP3832860A1 - Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire - Google Patents

Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire Download PDF

Info

Publication number
EP3832860A1
EP3832860A1 EP19213815.4A EP19213815A EP3832860A1 EP 3832860 A1 EP3832860 A1 EP 3832860A1 EP 19213815 A EP19213815 A EP 19213815A EP 3832860 A1 EP3832860 A1 EP 3832860A1
Authority
EP
European Patent Office
Prior art keywords
stator
electrical machine
movable element
rotor
air gap
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP19213815.4A
Other languages
German (de)
English (en)
Inventor
Michael Lampérth
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Phi Power Ag
Original Assignee
Phi Power Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Phi Power Ag filed Critical Phi Power Ag
Priority to EP19213815.4A priority Critical patent/EP3832860A1/fr
Priority to PCT/EP2020/084698 priority patent/WO2021110948A1/fr
Priority to US17/782,637 priority patent/US20230032576A1/en
Priority to CN202080083954.7A priority patent/CN114747123A/zh
Publication of EP3832860A1 publication Critical patent/EP3832860A1/fr
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
    • H02K41/02—Linear motors; Sectional motors
    • H02K41/03—Synchronous motors; Motors moving step by step; Reluctance motors
    • H02K41/031—Synchronous motors; Motors moving step by step; Reluctance motors of the permanent magnet type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/02—Details of the magnetic circuit characterised by the magnetic material
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K1/00—Details of the magnetic circuit
    • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
    • H02K1/22—Rotating parts of the magnetic circuit
    • H02K1/27—Rotor cores with permanent magnets
    • H02K1/2793—Rotors axially facing stators
    • H02K1/2795—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets
    • H02K1/2796—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets where both axial sides of the rotor face a stator
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K16/00—Machines with more than one rotor or stator
    • H02K16/04—Machines with one rotor and two stators
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/02—Details
    • H02K21/021—Means for mechanical adjustment of the excitation flux
    • H02K21/022—Means for mechanical adjustment of the excitation flux by modifying the relative position between field and armature, e.g. between rotor and stator
    • H02K21/025—Means for mechanical adjustment of the excitation flux by modifying the relative position between field and armature, e.g. between rotor and stator by varying the thickness of the air gap between field and armature
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/02—Details
    • H02K21/021—Means for mechanical adjustment of the excitation flux
    • H02K21/022—Means for mechanical adjustment of the excitation flux by modifying the relative position between field and armature, e.g. between rotor and stator
    • H02K21/025—Means for mechanical adjustment of the excitation flux by modifying the relative position between field and armature, e.g. between rotor and stator by varying the thickness of the air gap between field and armature
    • H02K21/026—Axial air gap machines
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/003—Couplings; Details of shafts
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K2201/00—Specific aspects not provided for in the other groups of this subclass relating to the magnetic circuits
    • H02K2201/03—Machines characterised by aspects of the air-gap between rotor and stator

Definitions

  • the present invention relates to an electrical machine, a vehicle comprising an electrical machine and a method for controlling the operation of an electrical machine.
  • Electrical machines that are used as electric motors or generators can convert electrical energy into mechanical energy and vice versa, wherein the underlying physical principles are well known in the art.
  • electrical machines and their development have attracted a lot of attention, as they are expected to play an important role for improving the performance of electric and hybrid vehicles.
  • Enhanced electrical machines could provide a significant contribution to reducing the dependence on petroleum-based fuels, while at the same time allowing for a more sustainable management of global resources.
  • comprehensive research was conducted in the field to arrive at improved electrical machines.
  • An axial flux electrical machine is a motor or generator with at least one rotor and at least one stator in which the magnetic flux between the rotor and the stator is parallel to the axis of rotation of the rotor.
  • Axial flux electrical machines have been used in niche automotive applications for many years where their shape and compactness offer specific benefits, for example when used as integrated electrical machines for hybrid powertrains. Overall market acceptance for axial flux electrical machines increased over the last decade, as they are known to offer excellent power and torque densities.
  • axial flux electrical machines can be designed with a single rotor and a single stator (often referred to as “single-sided” design), with a single rotor in between two stators (often referred to as “central rotor” design) or with a single stator in between two rotors (often referred to as "central stator” design).
  • WO 01/11755 A1 discloses a central rotor axial flux electrical machine.
  • an electric axial flow machine comprising an ironless disc-shaped rotor, which is arranged on a machine shaft, and two stators, which are arranged next to the rotor, wherein the rotor comprises permanent magnets which are embedded in a fiber-reinforced or fabric-reinforced plastic and wherein the permanent magnets are each joined with positive fit to the surrounding plastic to form a dimensionally stabile unit with the machine shaft.
  • WO 20018/003990 A2 discloses an axial flux electrical machine including a rotor mounted adjacent at least one stator, the rotor being mounted on a rotatable member for rotation relative to the stator such that the rotor and stator form a first rotor-stator module of the machine, wherein the machine includes a plurality of rotor-stator modules each substantially as the first module and axially-adjacent thereto, with each rotor being mounted on the rotatable member.
  • WO 2009/087376 A2 discloses a rotor for an axial flux electrical machine, the rotor having a plurality of permanent magnets fixed thereto, wherein each of the plurality of magnets extends at least partly through an aperture in the rotor, the arrangement being such that material of the rotor abuts the magnet so as to locate the magnet substantially circumferentially with respect to the axis of rotation of the rotor and substantially axially in at least one axial direction.
  • Axial flux electrical machines with central stator design require rotors with rotor yokes that can function as return paths for the magnetic flux. While these electrical machines are very compact and do not require a stator yoke, i.e. a path for the magnetic flux in the central stator, the two rotating disks at its sides often make integration into vehicles and sufficient cooling, in particular indirect cooling, of the electrical machine comparably challenging, wherein in particular the rotor yoke can suffer from undesirable heat build-up. Furthermore, the rotor inherently needs to be laminated in order to minimise eddy currents and hysteresis losses.
  • axial flux electrical machines with central rotor design are often preferably.
  • the magnetic flux passes from the first stator through the rotor to the second stator, wherein the second stator (like in the first stator) acts as a return path for the magnetic flux for closing the magnetic circuit.
  • two stationary stator rear faces are available for fitting the electrical machine into a vehicle and for arranging cooling elements.
  • axial flux electrical machines with central rotor design these electrical machines consist of a lot of different parts and often are found to be comparably difficult to assemble or to maintain.
  • axial flux electrical machines with central rotor design can be comparably heavy.
  • the most favourable type of axial flux electrical machines with respect to the number of required parts and weight of the machine are those electrical machines with a single-sided design.
  • these machines due to the fact that these machines only circulate the magnetic flux between a single stator and a single rotor, they in most cases also offer the lowest power.
  • only one side of the machine is formed by a stationary stator, adversely affecting both the incorporation into a vehicle and the cooling efficiency when compared to the central rotor design.
  • the most important drawback of these machines is the strong attraction force between the rotor and the stator which can be several kN in magnitude. This strong attraction force often leads to increased wear in the electrical machine, e.g. of the bearings that connect the stator with the shaft, reduces its resistance to impacts or other external forces and results in technical defects often having comparably severe, i.e. dangerous and damaging, effects on the electrical machine and/or the vehicle.
  • a passive stator does not comprise windings itself and in its most basic form only consists of a stator core, with optional components like for example cooling systems.
  • the inventors found that the addition of a passive stator solves the above described problems, if the passive stator is arranged opposite to the first stator, i.e. the active stator comprising the windings, on the other side of the rotor. This arrangement has the effect that the magnetic flux no longer circulates between the active stator and the rotor, thereby causing large attraction forces.
  • the magnetic circuit of the electrical machine is changed so that the magnetic flux passes from the active stator through the rotor to the passive stator, that acts as a return path for the magnetic flux, thereby e.g. removing the need for a rotor yoke, i.e. the backbone of the rotor that is used as return path for the magnetic flux in the single-sided design, thus allowing the use of the same rotors as for a central rotor axial flux electrical machine.
  • the passive stator does not comprise windings and does not require any wiring. Therefore, the passive stator can be designed to be very light, simple, robust and easy to assemble. In combination with the removal of the rotor yoke, this finding allows for a particularly lightweight electrical machine that can be build using a comparably low number of parts.
  • the resulting electrical machine has the same amount of air gaps as an electrical machine with a central rotor design and also features two stationary elements at its ends that shield the moving rotor, allow for an efficient cooling, facilitate safe operation and enable a convenient incorporation into vehicles. As the axial force on the rotor is greatly reduced, this design allows for high strength magnets to be used, resulting in high torque and power to weight ratios.
  • stator slots that means the structures in the stator that are designed for housing the windings.
  • the machine length can be reduced by the length of the tooth-tip of the stator tooth (i.e. the inward-bent terminal protrusions at the end of the stator tooth that are typically forming the stator slots).
  • the high reliability of the passive stator design found by the inventors can be understood when considering the magnetic circuit of the passive stator design compared to the magnetic circuit of a single-sided design.
  • the magnetic reluctance, or magnetic resistance corresponds to the electrical resistance.
  • the highest resistance, i.e. magnetic reluctance, in the electrical machine is expected to be caused by the air gaps, i.e. the free space or clearance between the components of the magnetic circuit.
  • problems in the operation of an electrical machine are primarily associated with undesired and/or unexpected changes in the system.
  • the magnetic flux passes from the active stator through the first air gap, through the rotor and through the second air gap to the passive stator, wherein the second stator acts as a return path for the magnetic flux that correspondingly returns through the second air gap, the rotor and the first air gap towards the active stator.
  • the total air gap i.e. the sum of the first and second air gap as well as the rotor thickness will always remain constant between the two stationary components (unless deliberately changed as a method for controlling the electrical machine), i.e. between the active and the passive stator, resulting in a beneficially stable and reliable electrical machine.
  • air gap as used in some prior art documents sometimes corresponds to the total air gap calculated as the sum of the rotor thickness as well as the first and second air gap that are used in the framework of the present invention for describing the electrical machine.
  • the first and second air gap correspond to the actual space between the rotor and the active or passive stator, respectively, that are sometimes also called mechanical air gaps by the skilled person.
  • the present invention was conceived during the development of improved axial flux electrical machines, as described above.
  • the inventors found that the inventive concept of a passive stator can also be applied to linear electric machines without modifications, as these electrical machines have several features in common with axial flux electrical machines. All the above described benefits can be obtained for linear electrical machines, if a passive stator comprising a stator core is arranged opposite to the active stator on the other side of the slider of a single-sided linear machine.
  • stator active stator
  • passive stator the invention is hereinafter disclosed using the terms first stator, i.e. the active stator as described above, and second stator, i.e. the passive stator described above.
  • first stator i.e. the active stator as described above
  • second stator i.e. the passive stator described above.
  • especially preferred is an electrical machine according to the invention, that defines two or more features of preferred embodiments of the present invention.
  • the invention relates to an Electrical machine comprising:
  • the first stator comprises a plurality of windings, preferably two or more, more preferably three or more, most preferably four or more.
  • Suitable windings are well known in the art and consist of windings of an electrical conductor that comprise e.g. copper and/or iron.
  • the windings can be connected to a power source and are used to generate the magnetic fields that drive the electrical machine.
  • the windings are typically arranged on the surface of the first stator that faces towards the movable element, wherein the windings are preferably arranged in a symmetric pattern.
  • the first stator comprises a plurality of stator slots that are designed for fixating the windings, wherein preferably the stator slots are formed by protrusions on the surface of the second stator, the so called stator tooth that preferably confine the stator slots with terminal tooth-tips.
  • the first and second stator each comprise a stator core that typically consist of materials that have a low magnetic reluctance, e.g. iron or steel, to allow for the magnetic flux to flow though the stator core, thereby functioning as a stator yoke.
  • the windings are preferably arranged on the surface of the stator core or in apertures in the stator core that are designed for housing the windings.
  • the second stator is typically laminated with the material having low magnetic reluctance, in order to minimise eddy currents and hysteresis losses.
  • the movable element is either a slider or a rotor that is connected to a shaft.
  • the electrical machine is a linear electrical machine and in case of the second alternative it is an axial flux electrical machine.
  • the movable element will comprise one or more magnetic elements, e.g. permanent magnets or windings, preferably permanent magnets.
  • the rotor is of a magnetically and/or electrically insulating material. This assists in avoiding losses in the rotor, such as losses due to eddy currents, and assists in avoiding magnetic short circuits in the flux path.
  • the rotor may be of a heat insulating material and may be resistant to high temperatures.
  • the movable element is movably mounted adjacent to the first stator to form a first air gap between the movable element and the windings of the first stator.
  • the electrical machine comprises a second stator that is arranged opposite to the first stator on the other side of the movable element, wherein the movable element is movably mounted adjacent to the second stator to form a second air gap between the movable element and the stator core of the second stator.
  • Movably mounted means that the movable element has at least one degree of freedom with respect to the stator, either rotational or translational.
  • the rotor can rotate around the axis of the shaft, while the slider of a linear electrical machine has at least one translational degree of freedom.
  • the term adjacent needs to be construed to mean that the two elements that are adjacent to each other are arranged in vicinity to each other, without actually being in contact, thereby forming an air gap that is sufficiently broad to allow for a free movement of the components relative to each other, even during operation at high speeds.
  • Typical air gaps between the movable element and the first or second stator are in the range of 0.3 to 2.5 mm. Therefore, the closest distance between the movable element and the first and/or second stator is preferably in the range of 0.3 to 2.5.
  • the first and second air gaps between the movable element and the first and second stator, respectively are essentially of the same size.
  • first and second air gap refer to the actual space between the movable element and the first or second stator, respectively.
  • the first and second air gap describe the part of the gap between the movable element and the respective stator, where during operation the magnetic flux passes from one structure to the other, i.e. typically the pathway of lowest magnetic reluctance. This is in agreement with the understanding of the skilled person.
  • the air gap is the gap formed between the windings and the rotor and not between the rotor and the stator core of the first stator.
  • An air gap that comprises one or more additional elements between the movable element and the stator can also be considered an air gap, as long as the contribution of the additional element to the total magnetic reluctance between the movable element and the respective stator is less than 5%.
  • a protective coating that is covering the windings or a thin fabric between the stator and the slider would not affect the status of the clearance between the elements to be a first or second air gap.
  • air gap defines the space between two elements and does not define that it is actually filled with air.
  • an air gap that is filled with a liquid cooling fluid or a different gas would still be an air gap within the meaning of the present invention.
  • an electrical machine wherein the movable element is only separated from the windings of the first stator by the first air gap and only separated from the stator core of the second stator by the second air gap, so that during operation the magnetic flux passes from one stator to the other through the first and second air gap as well as the movable element without passing through any additional condensed matter.
  • the first air gap is formed between the movable element and the windings of the first stator and the second air gap is formed between the movable element and the stator core of the second stator.
  • the first stator, the second stator and the movable element are arranged so that during operation of the electrical machine the magnetic flux passes from the first stator through the first air gap, through the movable element and through the second air gap to the second stator, wherein the second stator acts as a return path for the magnetic flux.
  • the electrical machine of the invention needs to be operational and that e.g. any arbitrary placements of the second stator are not considered to be according to the invention.
  • almost no magnetic flux that means less than 2 % of the magnetic flux, preferably no magnetic flux, turns in the movable element itself in order to directly flow back to the first stator.
  • the moveable element does not require a yoke.
  • this feature also excludes electrical machines that circulate the magnetic flux exclusively, or at least mostly, that means to more than 10 %, between the first stator and the movable element, like for example external-rotor motors or single-sided electrical machines.
  • the term return path means that the magnetic flux that enters the stator core of the second stator circulates through, that means flows through, the stator core in order to exit the stator core of the second stator at a different location, so that it can pass back to the first stator by passing through the second air gap, the movable element and the first air gap.
  • the second stator comprises no windings on the surface facing the movable element, and/or wherein the movable element comprises no yoke as return path for the magnetic flux.
  • the most basic embodiment of the present invention that is particular cheap and requires a minimum of valuable resources like copper, can be obtained. Furthermore, the effort of winding two stators is reduced.
  • an electrical machine comprising:
  • the concept of the present invention can be efficiently applied to axial flux electrical machines and linear electrical machines.
  • the electrical machine is an axial flux electrical machine, wherein the movable element is a rotor that is connected to a shaft and rotatably mounted between the first stator and the second stator, or wherein the electrical machine is a linear electrical machine, wherein the movable element is a slider that is movably mounted between the first stator and the second stator.
  • the movable element comprises two or more permanent magnets, wherein preferably the permanent magnets are arranged so that the polarity of each is opposite that of each immediately neighbouring magnet.
  • Suitable permanent magnets are known in the art. Electrical machines with permanent magnets have proven to be very robust and are comparably easy to manufacture. The usage of permanent magnets requires no additional wiring in the rotor. With respect to the performance of the electrical machine it was found beneficial to provide for a high density of magnets on the movable element. As an economically viable alternative, it is preferred to use soft magnetic steel, that means electrical steel or materials with similar magnetic properties, instead of permanent magnets.
  • the movable element is flat and comprises a structure for housing permanent magnets, preferably a disk or plate with apertures for housing permanent magnets, wherein the disk or plate is designed to restrict the movement of the permanent magnets in axial and/or radial direction, preferably in axial and radial direction, wherein most preferably the disk or plate comprises less than 30 % by weight of magnetic material, preferably less than 10 %, more preferably no magnetic material.
  • the unfavourable usage of magnetic material i.e. in most cases a metal, can be avoided in favour of cost efficient and lightweight materials like composite materials or plastics.
  • the thickness of the movable element can be reduced in order to further optimize the weight of the electrical machine.
  • the movable element comprises a structure for housing the permanent magnets, thereby restricting the translational degrees of freedom of the permanent magnets in axial and/or radial and/or tangential direction, preferably in axial, radial and tangential direction.
  • the permanent magnets are fixated in the movable element so that they cannot detach from the movable element during operation and can transfer the torque or force experienced during operation to the movable element.
  • the movable element is a rotor that is connected to a shaft, wherein the shaft extends through the first and/or second stator, wherein preferably the first and/or second stator is connected to the shaft with a bearing, preferably a roller bearing, to allow rotation of the shaft and the rotor relative to the first and/or second stator.
  • a bearing preferably a roller bearing
  • the stator core of the first and/or second stator comprises one or more materials selected from the group consisting of non-oriented and grain-oriented metal and soft magnetic material, preferably a non-oriented or grain-oriented electrical steel, more preferably a grain-oriented electrical steel.
  • non-oriented materials are oftentimes the most cost efficient solution
  • grain oriented electrical steel was found to be highly promising as it enables the design of specific stator cores with anisotropic magnetic reluctance and/or very low magnetic reluctance along a specific direction that can be fine-tuned to match the pathway of the magnetic flux in the electrical machine.
  • stator core of the first and/or second stator preferably of both stators is ring-shaped.
  • the respective shape of the stator core was identified to be an optimized trade-off between reduced weight and costs on the one hand and acceptable performance parameters of the electrical machine on the other hand.
  • the second stator is designed so that the distance between the second stator and the movable element can be varied during operation of the electrical machine, wherein the second stator is preferably designed so that the distance between a first portion of the second stator and the movable element can be varied during operation of the electrical machine, independent from the distance between a second portion of the second stator and the movable element.
  • an active stator that is the first stator of the electrical machine of the present invention
  • reservations can exist against changing the relative distance between an active stator and a movable element during operation of an electrical machine, in particular for a single-sided design.
  • the second stator i.e. a passive stator that forms the air gap with the movable element through its stator core, can readily be repositioned with respect to the movable element, thereby mechanically changing the magnetic reluctance of the air gaps and the magnetic properties of the electrical machine.
  • the desired effect can be obtained by moving only a portion of the second stator, and correspondingly only a portion of its stator core, relative to the movable element.
  • the benefit of this design is, that it allows for a modification of the magnetic circuit by effectively modifying the yoke of the second stator, without the need of moving any parts in the direct vicinity of the movable element that moves at high speed and/or exerts strong forces. This reduces the likelihood of failures due to undesired contacts between the movable element and the second stator.
  • first and/or the second stator comprise means for cooling the electrical machine, preferably cooling plates and/or isolating elements and/or parts of a fluid-based cooling system.
  • the respective electrical machines are beneficial as they make good use of the fact that the electrical machine according to the invention offers two stationary components to position means for cooling.
  • the windings are windings of an electrical conductor that comprise copper and iron, wherein the windings are electrically connected with a power source, wherein preferably the windings are arranged on the surface of the first stator with C 2 rotational symmetry or higher, most preferably C 6 rotational symmetry or higher.
  • the respective electrical machines are beneficial as the above windings and the corresponding arrangements were found to be particular suitable arrangements and components for the construction of an electrical machine that can provide high power densities.
  • the usage of windings of an electrical conductor that comprise copper and iron was found to be a cost efficient alternative to silver and other expensive conductors, that still works satisfactorily.
  • the second stator comprises at least one sensor unit, preferably a temperature or hall sensor, preferably a hall sensor for analysing the position of the movable element.
  • Suitable sensor units are well-known in the art.
  • the respective electrical machines are beneficial as the usage of sensors enables for an enhanced control of the electrical machine and allows to gather vital information about the machine during operation. Compared to the other designs of electrical machines that are known in the art, such electrical machines offer a lot more space for placing the respective sensor units as the second stator comprises no windings in the vicinity of the movable element.
  • the second stator typically comprises no windings and no associated wiring, it is typically possible to significantly reduce the noise that is captured by the sensor units during operation of the electrical machine.
  • the respective electrical machine provides very accurate measurement results even during operation of the machine.
  • the inventive concept of the present invention it is possible to significantly reduce the attraction force between the first stator and the movable element.
  • the skilled person is readily able to adjust the attraction force to the required level.
  • the inventors found that the attraction force should fall below specific thresholds for specific applications to ensure the highest possible degree of safety, wherein this criterion can be measured during testing of the electrical machine.
  • an electrical machine is preferred, wherein the average distance between the movable element and the first stator that is measured at the circumference of the movable element, changes by less than 5%, preferably less than 2%, most preferably by less than 0.5 % between inactive status and operation of the axial flux electrical machine, and/or wherein the axial attraction force between the movable element and the first stator is less than 500 N, preferably less than 100 N.
  • the electrical machine of the present invention allows for the design of axial flux electrical machines that can generate large torque and feature very high power to volume ratios.
  • an electrical machine according to the invention is preferred, wherein the axial flux electrical machine is designed to generate a torque of 200 Nm or more, wherein the axial flux electrical machine preferably has a power to volume ratio of 20 kW/L or more, preferably 30 kW/L or more.
  • the axial flux electrical machine preferably has a torque to volume ratio of 40 Nm/L or more, preferably 50 Nm/L or more.
  • the invention also relates to a method for controlling the operation of an electrical machine according to the invention, comprising the step of:
  • the invention also relates to a vehicle comprising an electrical machine according to the invention.
  • Figures 1 to 12 show cross-sectional views through schematic, exemplary electrical machines that shall facilitate the understanding of the present invention.
  • the figures show a cross-sectional view through a round structure that means, that the rotor 2 is a round plate, while the cooling plates 6, the bearings 5 and the stator core 3 are actually ring-shaped, wherein a plurality of windings 4 is arranged over the entire circumference of the ring-shaped stator core 3.
  • black arrows give a qualitative indication of the magnetic flux in the different electrical machines, while double arrows indicate that the position of the second stator 12 can be varied.
  • the qualitative indication of the magnetic flux is limited by the restraints of the cross sectional view. It should be understood that the magnetic flux flows through the ring-shaped stator core 3 and will not pass through the centre of the ring-shaped stator core 3 or the shaft 2 of the machine. In any case, the qualitative indication of the magnetic flux is meant to facilitate understanding of the invention and should not be construed to be limiting in any way.
  • Figure 1 depicts a prior art axial flux electrical machine having a central rotor design.
  • the rotor 1 is sandwiched between two first stators 11, that comprise a plurality of windings 4 and a stator core 3 as well as a cooling plate 6 that supports the stator core 3 and is connected to the shaft 2 through bearings 5 in order to allow for the rotor to be movably mounted adjacent to the first stator to form a first air gap 7 between the movable element and the windings 4 of the first stator 11.
  • Figure 2 shows the corresponding linear electrical machine with a slider 9 that is sandwiched between two first stators 11.
  • the single-sided design for these electrical machines is obtained when one of the active stators 11 is removed, leaving only one movable element that is movably mounted adjacent to the first stator 11 to form a first air gap 7 between the movable element and the windings 4 of the first stator 11.
  • a schematic representation of these single-sided designs is shown in figures 3 and 4 , wherein figures 7 and 8 also provide qualitative indication of the magnetic flux in the respective electrical machines.
  • Figures 5 and 6 disclose electrical machines according to the invention, wherein figure 5 shows an axial flux electrical machine having a rotor 1 connected to a shaft 2 while figure 6 shows a linear electrical machine having a slider 9. Furthermore, figures 9 and 10 qualitatively indicate the magnetic flux in the respective electrical machines.
  • the invention and the underlying inventive concept of the passive stator will be explained in detail for figure 5 .
  • Figure 5 shows a cross-sectional view through an axial flux electrical machine that on its right side comprises a first stator 11 comprising a stator core 3 and a plurality of windings 4.
  • a movable element that is a rotor 1
  • the rotor 1 is connected to a shaft 2.
  • a second stator 12 comprising a stator core 3 is arranged opposite to the first stator 11 on the other side of the rotor 1, wherein the rotor 1 is rotatably mounted adjacent to the second stator 12 to form a second air gap 8 between the rotor 1 and the stator core 3 of the second stator 12.
  • the first stator 11, the second stator 12 and the rotor 1 are arranged so that during operation of the electrical machine the magnetic flux passes from the first stator 11, more precisely from its stator core 3, through the first air gap 7, through the rotor 1 and through the second air gap 8 to the second stator 12, more precisely to its stator core 3, wherein the second stator 12, more precisely its stator core 3, acts as a return path for the magnetic flux.
  • This is visualized in figure 9 .
  • the second stator 12 comprises no windings 4 on the surface facing the rotor 1 and the rotor 1 comprises no yoke as return path for the magnetic flux.
  • the rotor 1 comprises a plurality of permanent magnets, that are arranged so that the polarity of each is opposite that of each immediately neighbouring magnet.
  • the rotor 1 is flat and comprises a disk with apertures for housing the permanent magnets, wherein the disk restricts the movement of the permanent magnets in axial and radial direction.
  • the rotor 1 is for example made from a non-magnetic composite material.
  • the shaft 2 extends through the first 11 and second stator 12, wherein the first 11 and second stator 12 are connected to the shaft 2 with a roller bearing 5, to allow rotation of the shaft 2 and the rotor 1 relative to the first 11 and second stator 12.
  • the rotor 1 is only separated from the windings 4 of the first stator 11 by the first air gap 7 and only separated from the stator core 3 of the second stator 12 by the second air gap 8, so that during operation the magnetic flux passes through the first 7 and second air gap 8 as well as the rotor 1 without passing through any additional condensed matter.
  • the windings 4 are for example windings 4 of an electrical conductor that comprise copper and iron, that are electrically connected with a power source, wherein the windings 4 are for example arranged on the surface of the first stator 11 with C 12 rotational symmetry.
  • Figures 11 and 12 show electrical machines according to the invention wherein the magnetic reluctance of the first air gap 7 and the second air gap 8 is modified by varying the distance between the second stator 12 and the rotor 1 or the slider 9, respectively.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Electromagnetism (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
EP19213815.4A 2019-12-05 2019-12-05 Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire Pending EP3832860A1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP19213815.4A EP3832860A1 (fr) 2019-12-05 2019-12-05 Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire
PCT/EP2020/084698 WO2021110948A1 (fr) 2019-12-05 2020-12-04 Machine électrique à flux axial unilatéral avec stator passif supplémentaire
US17/782,637 US20230032576A1 (en) 2019-12-05 2020-12-04 Single sided axial flux electrical machine with additional passive stator
CN202080083954.7A CN114747123A (zh) 2019-12-05 2020-12-04 具有附加无源定子的单面轴向磁通电机

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19213815.4A EP3832860A1 (fr) 2019-12-05 2019-12-05 Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire

Publications (1)

Publication Number Publication Date
EP3832860A1 true EP3832860A1 (fr) 2021-06-09

Family

ID=68806663

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19213815.4A Pending EP3832860A1 (fr) 2019-12-05 2019-12-05 Machine électrique à flux axial unilatéral comportant un stator passif supplémentaire

Country Status (4)

Country Link
US (1) US20230032576A1 (fr)
EP (1) EP3832860A1 (fr)
CN (1) CN114747123A (fr)
WO (1) WO2021110948A1 (fr)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019216844A1 (de) * 2019-10-31 2021-05-06 Robert Bosch Gmbh Axialflussmaschine für ein elektrisches Bearbeitungsgerät sowie elektrisches Bearbeitungsgerät mit einer Axialflussmaschine

Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0660494A1 (fr) * 1993-12-21 1995-06-28 Gec Alsthom Transport Sa Machine synchrone à aimants à variation de flux d'entrefer
JPH10243589A (ja) * 1997-02-26 1998-09-11 Canon Inc モータ用コイル及びモータ
WO2001011755A1 (fr) 1999-08-09 2001-02-15 Perm Motor Gmbh Machine electrique a flux axial
US20070046124A1 (en) * 2005-09-01 2007-03-01 Metin Aydin Field controlled axial flux permanent magnet electrical machine
WO2008006906A1 (fr) * 2006-07-14 2008-01-17 Nexxtdrive Limited Machine électrique rotative à aimants permanents
US20090134723A1 (en) * 2007-11-22 2009-05-28 Seiko Epson Corporation Electric motor device
WO2009087376A2 (fr) 2008-01-07 2009-07-16 Evo Electric Limited Rotor pour machine électrique
US20100071972A1 (en) * 2006-07-07 2010-03-25 Michael Ulrich Lamperth Electrical machine
WO2012059753A1 (fr) 2010-11-04 2012-05-10 Evo Electric Limited Machines électriques à flux axial
WO2014108111A2 (fr) 2012-12-20 2014-07-17 Klaus-Dieter Nies Rotor pour un arbre d'une machine électrique à flux axial
US20150171722A1 (en) * 2013-12-17 2015-06-18 Fanuc Corporation Linear drive unit having linear motor and machine tool
FR3022708A1 (fr) * 2014-06-20 2015-12-25 Whylot Moteur electromagnetique lineaire a entrainement direct et a double entrefer avec reduction de la force de detente dans le moteur electromagnetique
WO2018003990A1 (fr) 2016-06-30 2018-01-04 有限会社ショウナンエンジニアリング Transporteur magnétique de copeaux
US20190002214A1 (en) * 2017-06-29 2019-01-03 B&R Industrial Automation GmbH Method for operating a transport apparatus in the form of a long stator linear motor

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4837467A (en) * 1987-12-02 1989-06-06 North American Philips Corporation Linear motor with angularly indexed magnetic poles
NL1012571C2 (nl) 1999-07-12 2001-01-15 Ravas Europ B V Palletwagen.
US7432623B2 (en) * 2001-03-08 2008-10-07 Apex Drives Laboratories, Inc. Brushless electromechanical machine

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0660494A1 (fr) * 1993-12-21 1995-06-28 Gec Alsthom Transport Sa Machine synchrone à aimants à variation de flux d'entrefer
JPH10243589A (ja) * 1997-02-26 1998-09-11 Canon Inc モータ用コイル及びモータ
WO2001011755A1 (fr) 1999-08-09 2001-02-15 Perm Motor Gmbh Machine electrique a flux axial
US20070046124A1 (en) * 2005-09-01 2007-03-01 Metin Aydin Field controlled axial flux permanent magnet electrical machine
US20100071972A1 (en) * 2006-07-07 2010-03-25 Michael Ulrich Lamperth Electrical machine
WO2008006906A1 (fr) * 2006-07-14 2008-01-17 Nexxtdrive Limited Machine électrique rotative à aimants permanents
US20090134723A1 (en) * 2007-11-22 2009-05-28 Seiko Epson Corporation Electric motor device
WO2009087376A2 (fr) 2008-01-07 2009-07-16 Evo Electric Limited Rotor pour machine électrique
WO2012059753A1 (fr) 2010-11-04 2012-05-10 Evo Electric Limited Machines électriques à flux axial
WO2014108111A2 (fr) 2012-12-20 2014-07-17 Klaus-Dieter Nies Rotor pour un arbre d'une machine électrique à flux axial
US20150171722A1 (en) * 2013-12-17 2015-06-18 Fanuc Corporation Linear drive unit having linear motor and machine tool
FR3022708A1 (fr) * 2014-06-20 2015-12-25 Whylot Moteur electromagnetique lineaire a entrainement direct et a double entrefer avec reduction de la force de detente dans le moteur electromagnetique
WO2018003990A1 (fr) 2016-06-30 2018-01-04 有限会社ショウナンエンジニアリング Transporteur magnétique de copeaux
US20190002214A1 (en) * 2017-06-29 2019-01-03 B&R Industrial Automation GmbH Method for operating a transport apparatus in the form of a long stator linear motor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
M. U. LAMPERTH ET AL., EVS 28 INTERNATIONAL ELECTRIC VEHICLE SYMPOSIUM AND EXHIBITION, 3 May 2015 (2015-05-03)

Also Published As

Publication number Publication date
WO2021110948A1 (fr) 2021-06-10
CN114747123A (zh) 2022-07-12
US20230032576A1 (en) 2023-02-02

Similar Documents

Publication Publication Date Title
EP2394351B1 (fr) Machine électrique
US10778049B2 (en) Stator assembly with stack of coated conductors
US7851965B2 (en) Transverse and/or commutated flux system stator concepts
US11784529B2 (en) Torque tunnel Halbach Array electric machine
US8994243B2 (en) Transverse and/or commutated flux systems having multidirectional laminations
JP2009540788A (ja) リングコイルモータ
JP2009545939A (ja) 力脈動補償を備えたリニアモータ
JP2015509259A (ja) 永久磁石を有する電磁アクチュエータおよびこのアクチュエータによって作動する機械的負荷遮断器
Masmoudi et al. Optimizing the overlap between the stator teeth of a claw pole transverse-flux permanent-magnet machine
WO2012036945A2 (fr) Rotor à aimant permanent pour machine électrique
Zhang et al. Mechanical construction and analysis of an axial flux segmented armature torus machine
US20110101817A1 (en) Variable geometry electric machine
JP2016518097A (ja) 磁束スイッチング変調磁極機械
US20200044494A1 (en) High-magnetic-flux discrete stator electrical machine
US20230032576A1 (en) Single sided axial flux electrical machine with additional passive stator
US20220407402A1 (en) Magnetic-geared motor
CN204231076U (zh) 电动机
WO2011089797A1 (fr) Rotor, machine électrique rotative utilisant celui-ci, et générateur d'électricité
Paveza et al. Design of a Double Rotor BLDC Motor with Halbach Array Magnets
JP5740250B2 (ja) 永久磁石式回転電機
KR20170058627A (ko) 전기 모터
CN108475975B (zh) 电机
CN113508515B (zh) 方位角或极向磁通机器
Mahmoudi et al. PM-Free Axial-Flux Motors for Transport Electrification
WO2024050085A1 (fr) Pièce polaire de machine électrique à flux axial comprenant des rubans conducteurs

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN PUBLISHED

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20211209

RBV Designated contracting states (corrected)

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20230912